1. Field of the Invention
This invention relates to a split voice coil and directly coupled push-pull amplifier circuit for a speaker.
2. Prior Art
Directly coupled split voice coils for audio speakers have been used with push-pull circuits. See, for example, U.S. Pat. No. 2,959,640 issued to J. B. Schultz. Circuits such as that shown by the Schultz patent and directly coupled to a speaker require stabilizing; i.e., a feedback circuit for the control of gain. In addition, to applicant's knowledge, direct-coupled split coil speakers have not been constructed to obtain maximum operating efficiency for a given speaker magnet size. For example, a relatively long excursion or travel of a speaker coil is advantageous in producing loud sounds; yet, the typical excursion of a speaker coil is kept small compared to the length of the magnetic gap in which it moves because inefficiencies result where portions of the energized coil are outside of the magnetic flux path, and distortion results if the amount of the coil within the flux path changes. Moreover, the magnet depth itself, which defines the gap length, is usually kept small because of the substantial expense of large magnets.